1. Field of the Invention
This invention relates generally to automatic elevator systems and in particular to means for providing supervisory control of normal operation modes of such elevator systems in response to an electrical signal.
2. Description of the Prior Art
In conventional automatic elevator systems a preconditioned control circuit means is provided to control the normal operation modes of the elevator. Regardless of how old an existing system may be, normal operation modes of elevator systems usually include the servicing of a plurality of reference floor levels by at least one car, the responding of such car to both hall call registers and car call registers, and the automatic opening and closing of at least one car door at each reference floor for which a call has been registered. Although these operations appear to be universal normal operations for elevator systems, it will be understood by those skilled in the art that an elevator system may include additional normal operation modes for which the control circuit means will have been preconditioned to control.
Recent events which have occurred in automatic elevator systems during emergency situations have resulted in legislation and new safety codes which require that all automatic elevator systems, both old and new, operate in certain abnormal operation modes when an emergency situation arises (See The American National Standards Institute's Safety Code for Elevators, ANSI A17.1, Section 211, 1973 and 1976 Supplements Thereto). Furthermore, even without legislation, it has become desirable to incorporate additional operation modes to update existing automatic elevator systems and to provide other safety features not necessarily required by any safety code or law. Many control circuits have been devised in order to implement added features to the normal operation modes of elevator systems of which U.S. Pat. Nos. 3,297,109; 3,726,364; 3,773,145, and 3,788,428 are exemplary. Naturally, these new control circuits require the incorporation of additional circuitry to the existing preconditioned control circuit means of each elevator system which is being modified in order to cause the elevator to operate in the desired abnormal operation mode in response to an electrical signal. Typically, modifying the preconditioned control circuit means has involved electrically coupling and mounting individual switching devices to the preconditioned control circuit means.
The incorporation of additional circuitry to modify the preconditioned control circuit means of elevator systems does not present any special problems if accomplished at the time of assembly of new preconditioned control circuit means; however, the incorporation of such additional circuitry into existing control circuit means does present problems due to the lack of space, remote locations of individual controls, and the variety of preconditioned control circuit means. Many existing automatic elevator systems are very old systems and very few have identical circuitry for controlling the normal operations of the elevator. In most instances where new and old elevator systems are required by law to incorporate circuitry which will cause them to operate as the law prescribes considerable time must be spent to incorporate individual switcing devices into each elevator system because of the problems enumerated above. There exists no universal means for providing additional supervisory circuitry to the large variety of preconditioned control circuit means of existing elevator systems. While it will be recognized by those skilled in the art that the present invention is most advantageously adaptable to existing automatic elevator systems it will also be recognized that the modular construction of the supervisory control means of the present invention allows it to be advantageously used in the manufacture and assembly of new elevator systems where laws require elevator systems to operate in certain abnormal modes under emergency conditions, since the supervisory control circuitry required to cause such abnormal operations will be integrated into a single module allowing for easy installation and maintenance of the added circuitry.
The modular supervisory control means of the present invention actually compliments those previously devised control circuits represented by the aforementioned U.S. patents for supervising the normal operation modes of an elevator system. Accordingly, the present invention is distinguishable from the U.S. patents cited above in that the present invention does not encompass any particular supervisory control circuit but rather is a universal means for providing a supervisory control circuit to an automatic elevator system.